Process and article for treating materials and article so produced



Patented July 18, 1944 units ST PATENT OFFEC PROCESS AND ARTICLE FORTREATING MATERIALS AND ARTICLE. S PRODUCED No Drawing. Application July19, 1940, Serial No. 346,332

lllainis.

The present invention relates to the art of finishing. Moreparticularly, it relates to a process of finishing in which a film isformed and transferred to an article for the purpose of decorating,varying the visual characteristics of the article, preserving and/orstrengthenin the article. The invention also relates to the transferarticle by which the film is applied to the article to be finished andto the finished article.

It is desirable that many articles such as magazine covers, pictorialand other advertising pages, prints, photographs, maps and covers forbooks and pamphlets be provided with finished surfaces in order toenhance their appearance and durability. However, the attainment of thisobject by the application to the articles of a film capable of producingthis result presents many difiicult problems. Such finishing filmsshould be capable of producing coloration, as desired, to

produce a, decorated efiect or of being made translucent to provide asoftening or toning effect. Such films should also be capable of beingmade clear and transparent so as to increase the brilliance of thesurface reflection or to clarify details of the articles, and for thesepurposes the films must have smooth and glossy surfaces which makes theproblem even more difiicult. It is frequently necessary also that such afilm serve to reinforce the article as well as protect it againstdefacement, either through accidental sources, such as wear, scratchingor the like, or intentional alteration.

Since many of these articles, for example, magazine advertisements orother advertising or decorative matter, depend almost entirely upon anattractive appearance for their effectiveness, it naturally follows thatanything which increases the attractive properties of these articlesenhances their functional value. For this reason,

the applied film must be capable of impartinga high gloss to the articleand to accomplish this the exposed surfaces of the applied film must beexceptionally smooth and free from blemishes. Also, the films must be ofsubstantially uniform thickness throughout in order to avoid unevenreflections of light and consequent distortion in the appearance of thearticle. This uniformity of thickness is also necessary if the appliedfilms are to function properly to accentuate and clarify details of thedesigns, pictures or the like carried by the base sheets beneath thefilms. Furthermore, such finishing films must be stable, both inappearance and Wearing properties, and to that end must tenaciouslyadhere to the articles so as to prevent variations in reflectiveproperties, and must in most cases remain transparent and unaffected bylight if the appearance of the finished article is to be preserved.Since such finishing films are positioned on the outermost portions ofarticles, they must be suificiently flexible to bend with the articleswithout becoming separated therefrom and must also be tough and strongso as not to be readily torn or otherwise deformed.

The process of producing such a finish must be simple in character andthe finish itself must be formed from inexpensive and readily availablematerials in order to prevent the cost from rendering the finishincapable of general application, since many of the articles to whichsuch a finish could be advantageously applied are relatively inexpensivearticles of commerce. To this end, the process should be marked by anabsence of expensive and complicated apparatus and must make it possibleto deposit a very thin film so as to avoid the use of excessivequantities of finishing material and unduly thickening the articles sofinished. In this connection, it should be noted that the use ofinferior grades of base material, such as paper, chip board and the likemay be employed and provided with any desired design since the finishingfilm fills up and evens out the inequalities in the surface of thearticles. Thus, the film must completely compensate for the inferiororiginal quality of the article and additionally strengthen andreinforce the article to enable it to withstand the conditions which itwill encounter while in use.

Many articles which can be advantageously finished in accordance withthe present process are subject to staining, dissolution of printing inkand the like by solvents and water, and for this reason the'process mustbe capable of use without employing organic solvents and water.Furthermore, certain finished articles may be brought into contact withfoodstuffs and the like, and for this reason the articles must be freefrom odors frequently attendent with the use of volatile organicsolvents.

Since the use of separate adhesives adds materially to the expense andcomplexity of the finishing operation and frequently leads to theproduction of inferior articles, it is desirable to avoid the use ofadhesives in the finishing process. On the other hand, the finishingfilms must tenaciously adhere to the articles and to this end thefinishing film itself must become very tacky at the time of application,at least throughout the area contacted by the article so as to becapable of adhering to the article, but at the same time must not adhereto anything else so as to deleteriously affect the smooth exteriorsurface of the finishing film.

It has been found that all of the foregoing desirabilities can beobtained in a facile manner by the use of materials which are inherentlythermoplastic and therefore quite tacky when heated to form decorative,protective and/or reinforcing films on an infinite number of articles byforming a film initially on a backing sheet formed of smooth,substantially non-porous material and then transferring the film to thearticle to be finished by the use of heat and pressure. In this manner,films which are too thin to be able to support their own weight and forthis reason could not be formed by extrusion processes and the like, canbe formed, handled and transferred without difficulty. Although it wouldseem that the extreme tackiness of the inherently thermoplastic materialat the time of heating incidental to the transfer operation wouldprevent the material from releasing from the backing sheet, it has beenfound that these materials will release from backing sheets formed ofsmooth materials in a clear cut and uniform manner so as to make theapplication of such films to articles possible at temperatures belowthose which would damage many delicate articles.

It is a general object of the present invention to provide a process offinishing articles which accomplishes all of the reviously mentioneddesirabilities.

It is a specific object of the present invention to provide a process offinishing articles so as to improve their visual characteristics andother physical properties.

It is also an object of the present invention to provide a process offinishing articles with a glossy, mirror-like surface.

It is another object of the present invention to provide a process offinishing articles with a covering of minute thickness.

It is a further object of the present invention to provide a process offinishing articles involving the use of relatively low temperatures toapply the finishing film to articles.

It is a still further object of the present invention to provide anarticle having an extremely thin finishing coating applied thereto.

It is also an object of the present invention to provide a transferarticle in the form of a backing sheet having a film for use in thepractice of the process of the invention.

Other objects and advantages, if not specifically pointed out, will beapparent to those skilled in the art as the description of the inventionproceeds.

The process of the present invention, in general, comprises suitablyapplying a layer of inherently thermoplastic material to a backing sheetof smooth, substantially non-fibrous material to form a transfer,contacting the film so formed with an article to be finished, applyingheat to the film and/or the article, exerting pressure to force the filminto tight contact with the article to cause adherence of the film tothe grticle, and stripping the backing sheet from the The articles ofthe present invention comprise, respectively, a backing sheet formed ofsmooth material and provided with a layer of inherently thermoplasticmaterial, and a finished article provided with an extremely thindecorative preservative and/or protective coating.

The invention accordingly comprises the sev- 1e resins and the like.

eral steps and the relation of one or more of such steps with respect toeach of the others.

and the articles possessing the features, prop-' erties, and therelation of elements, exemplified in the following detailed disclosure,and the scope of the invention will be indicated in the claims.

The film-forming material used in the practice of the present inventionmay be any inherently thermoplastic material, such as synthetic resins,for example, polyvinyl resins such as polyvinyl chloride, polyvinylacetate and the like; polystyrene, polymerized hydrocarbons such aspolyiso-butylene; copolymers, such as copolymers of vinyl halides andvinyl esters, vinyl derivatives and acrylo nitriles, vinyl derivativesand styrene derivatives; acrylic acid esters of aliphatic and arylalcohols. Thermoplastic cellulose derivatives may also be employed asthe film-forming material such, for example, as cellulose esters of thehigher fatty acids, such as cellulose stearate, cellulose palmitate,cellulose aceto-butyrate; alkyl and aryl cellulose ethers of high degreeof substitution, such as ethyl cellulose and the like. 'The followingmay also be used: sulfonamide-aldehyde resins; rubber hydrohalides;sulfur-olefin resins; cumarone resin; indene resin; condensationpalymers such as the condensation products formed from di-basic acidsand diamines (nylon type), and polyhydric alcohols and polybasic acids;chlorinated biphenyls, as well as natural and synthetic gums, andmixtures of any two or more of the aforementioned materials. Materialswhich are not inherently thermoplastic such, for example, as celluloseacetate, cellulose nitrate and the like, may be mixed in suchproportions with inherently thermoplastic materials that the resultingmixture will be inherently thermoplastic and used in the practice of thepresent invention.

The forming surface on which the thermoplastic materials are spread toform the thermoplastic film are preferably formed of some material whichhas little or no affinity for the thermoplastic material itself andwhich is not affected by the solvents and/or plasticizers used in suchmaterials. Such materials are non-fibrous cellulose material such ascellulose esters, for example, cellulose acetate and cellulose nitrate;regenerated cellulose, metal foil, thin sheets of infusible The materialwhich has been found most suitable for this purpose is regeneratedcellulose. This may be formed by regeneration of cellulose from viscoseor cuprammonium solutions of cellulose, zinc chloride solutions ofcellulose, or cellulose dissolved in organic solvents such as quaternaryammonium compounds, or by de-esterification of cellulose esters,de-etherification of cellulose ethers, or gelatinization of cellulose inthe form oi cotton linters, wood pulp and the like or from any othersource from which regenerated cellulose can be formed. The regeneratedcellulose is preferably shaped in the form of a sheet, herein called abacking sheet but may also be formed into a band or plate having asmooth surface upon which the thermoplastic material may be suitablyspread. The entire body having the film-forming surface need not beformed of regenerated cellulose and to this end the main portion of thebody may be formed of a cellulose ester, a cellulose ether or some othercellulosic derivative which may be suitably treated to convert thesurface to regenerated cellulose.

The use of'a non-fibrous material of this type enables the finishingfilm to have an exceptionally glossy, mirror-like finish since therelatively non-porous and non-fibrous surface of the backing sheetcauses the exposed surface of the finishing film to be smooth and highlyreflective of light. This greatly enhances the appearance of thefinished article. If desired, the smooth surface of the backing sheetmay be suitably roughened to cause the surface of the finishing film tobe dull instead of glossy,

The backing sheet may be in the form of individual sheets or may beformed as a roll or continuous belt, band or the like.

The inherently thermoplastic material may be disposed upon thefilm-forming surface of the backing sheet in the form of a molten massor solution by spraying, brushing, casting, backfilling or the like.From some aspects of the invention, it is preferable that thethermoplastic material be cast upon the transfer sheet in the form of aliquid of controlled consistency. By controlling the solids content andthe viscosity of the liquid, the thickness of the film can be accuratelycontrolled to produce a film of substantiallyany desired thickness.

The thermoplastic material may be suitably melted for application to thebacking sheet or may be formed into a solution in any manner well knownin the art by the use of a suitable solvent for the thermoplasticmaterial. of which there are many well known in the art for all of thethermoplastic materials exemplified above. Likewise, suitableplasticizers may be incorporated in the solution to produce a filmhaving the desired plasticity. The term solution" is used throughoutthis specification to mean a true solut on, colloidal dispersion or anyother liquefaction of the material. such as a molten mass or the like.After the thermoplastic material has been applied to the backing sheet,it is cooled and/or dried into a film by evaporation of the solvents inany desired manner, for example, by the use of heat and/or air, afterwhich it will be found that the thermoplastic film adheres to thebacking sheet with sufiicient tenacity for the sheet to be handledincidental to usage, and stored or shipped without rupturing the bondbetween the backing sheet and the film. The bond so formed is notsufiicient, however, to interfere with the application of the film to'anarticle to be finished by transferring the film from the sheet to thearticle. This can be accomplished by the use of relatively lowtemperatures and relatively low pressures so that the film itself, thebacking sheet and the article are not detrimentally affected by thetransfer process. The backing sheet may be re-used as many times asdesired, depending upon the care which is exercised in preserving thesheet during the transfer operation.

The transfer operation is effected by bringing the article to befinished into contact with the film on the backing sheet and applyingheat to the film and/or the article and suffic ent pressure to force thefilm into contact with and cause it to adhere to the article.

The backing sheet may then be stripped from the film, leaving the sametightly anchored to the article. It is preferable that the film andarticle be cooled prior to removing the backing sheet since less care isthen required in the stripping operation.

The heat and pressure exerted upon the backing sheet, film and articleduring the transfer process may be supplied by the use of heated platenplates of any well known type, heated calender rolls, steam presses andthe like.

By way of illustration and not in limitation of the invention, thefollowing example of the present invention will be given:

A copolymer of vinyl acetate and vinyl chloride was dissolved in acetoneto form a 10% solution of the copolymer by weight. A plasticizer soldunder the trade name Flexol 3 GH" was added to the extent of 10% of theplasticizer based on the dry weight of the copolymer. The solution soformed was cast by a conventional type of casting machine at roomtemperature onto a sheet of regenerated cellulose in the form of a sheetof plain Cellophane to form the transfer. The acetone was permitted toevaporate and a film of approximately 0.0002 inch thickness resulted.

The backing sheet bearing the film so formed was placed over a sheet ofhard finished paper resting on the lower plate of a press in which theplates were electrically heated to degrees C. The transfer was pressedagainst the paper under a pressure of 500 pounds per square inch forthree seconds. The press was then opened and the transfer and hardfinished paper were permitted to cool to room temperature when thebacking sheet was stripped from the film which remained tightly adheredto the paper. The paper was thereby provided with a glossy. transparentfinish approximately 0.0002 inch thick which adhered to the paper in thepresence of mo sture and withstood handling and folding without givingany indication of disengaging from the paper.

The thermoplastic material may have any suitable pigment, filler and/ordyestuff incorporated therein to impart any degree of coloring and/oropacity desired to the film. and may also have moistureproofing agentsadded thereto, such as waxes, oils. and the like, if desired.

The present process may be used to finish various kinds of fabrics, suchas paper, textiles and the like. as well as prints, paintings,photographs. maps, documents, and various articles formed from fibre,cardboard. linoleum. cork and the like.

The finish a plied to such articles by the present process enhancestheir visual characteristics by increasing their light reflectiveproperties and/or bringing out the details of the print or photographand, in addition, forms a protective surface which prevents defacementof the article, either intentionally or accidentally either mechanicallyor by the use of reagents such as acids, alkali and oxidation materials.The transfer films so formed do not shrink excessively when drying sinceinherently thermoplastic material contains less moisture in the gelstage than nonthermoplastic material. with the result that the backingsheet or the base sheet with the film attached will remain substantiallyindefinitely without warping or otherwise becoming distorted. Also, thefinished article bearing the film so formed may be bent and even foldedwithout fracturing the film or rupturing the bond between the film andthe base sheet. Films formed from inherently thermoplastic materialsalso are capable of expanding and contracting with the base sheet due tochanges in atmospheric conditions without cracking or stripping from thesheet. Such films tenaciously adhere to articles to which they areattached, and may be applied to such articles at comparatively lowtemperatures and pressures, which greatly increases the number ofarticles which can be so finished. In addition, films formed of suchmaterials do not tend to articles.

de-hydrate and thereby embrittle the sheet as is characteristic of otherfilms.

The films transferred in accordance with the present invention can bemade so thin as to be incapable of withstanding handling if unsupported,with the result that thinner and more uniform films can be applied toarticles than was heretofore possible. The articles so formed are markedby exceptional stability, striking appearance and a controlled thicknesswhich can be made very small in view of the thinness. It has been foundpractically impossible to handle films less than about .0006 inch thickheretofore so that films thinner than this could not be applied toWhereas, it is possible by use of the present invention to form andapply films of less than .0001 inch thickness.

The film may be applied continuously over the surface of the base sheetor may be applied in predetermined areas of any desired configuration toenhance or vary the appearance of or change the physical characteristicsof any desired portion of the base sheet.

The articles finished in accordance with the present invention may beembossed with any desired indicia and/or configurations on the film sideor opposite side or on both sides simultaneously with the application ofthe films to the base sheets by forming the pressure plates or rollerswith raised or depressed portions of any desired shape.

Since certain changes in carrying out the above process, and certainmodifications in the article which embody the invention may be madewithout departing from its scope, it is intended that all.

matter contained in the above description shall be interpreted asillustrative and not in a limiting sense.

We claim:

1. A transfer, adapted for use in the coating of a surface with acoating of a synthetic resinous material, which has a backing sheetcomprising a smooth, glossy, non-fibrous cellulosic film and a normallynon-tacky thermoplastic coating there'- on comprising a synthetic resintemporarily adhered directly to said cellulosic film to provide forhandling incident to transfer but having substantially no chemicalafllnity to cause permanent adhesion thereto, said coating beingreleasable to permit transfer of the coating to the surface to be coatedupon the contact of said coating therewith and the application of heatto render said coating tacky.

2. The transfer product of claim 1 wherein the smooth, glossy,non-fibrous cellulosic film comprises non-fibrous regenerated cellulose.

3. The transfer product of claim 1 wherein the smooth, glossy,non-fibrous cellulosic film comprises a non-thermoplastic celluloseester.

4. The transfer product of claim 1 wherein the coating comprises acopolymer of vinyl compounds.

5. The transfer product of claim 1 wherein the coating of syntheticresin is less than .0006 of an inch thick.

CARLE'I'ON S. FRANCIS, JR. WORTH WADE.

